Method of making catalysts



June 3, 1941- G. ROBERTS, JR 2,244,573

METHOD oF MAKING CATALYSTS I Filed July 18, 1938 2 Sheets-Sheet 1 INVENTOR BeYa/ye Fae/zf//f ATTORMEY June 3, 1941. G. RoBERTs, JR

METHOD OF MAKING CATALYSTS Filed July 18, 1938 2 Sheets-Sheet 2 lll' ATTOR Y Patented June 3, 19431 METHOD F MAKING (.'HYIALYS'ISV George Roberts, Jr., Montclair, N. J., assignor to The M. W. Kellogg Company, New York, N. Y., a corporation of Delaware Application July 18, 1938, Serial No. 219,931

4 Claims.

My invention relates to a method of making a catalyst and more particularly. a catalyst adapted for useA in the catalytic conversion of hydrocarbons, as for example, the conversion of high boiling hydrocarbons to low boiling hydrocarbons or the synthesis oi hydrocarbons from mixtures of carbon monoxide and hydrogen.

Suitable catalysts for these operations are 'iinely divided'metals such as cobalt, nickel, iron, and the like, supported upon a suitable material such as kiesel'guhr, silica or the like.

A nickel catalyst is cheaper per pound than a cobalt cataylst, but more nickel catalyst is required. All catalysts, after a period of use, decline in activity and must be re-worked. In the case of a nickel catalyst, since greater amounts are necessary in a given operation andV since its life may not be so long as cobalt catalyst, the re-working cost of a nickel catalyst is greater.

I have determined that a cobalt catalyst, having approximately the following composition is, from an economical point of view, taking into consideration the cost of re-working, an excellent one. It is understood that it is given by way of example and not by way of limitation, since my method is applicable to any suitable catalyst metal.

Weight (percent) One object of my invention is to provide a method of manufacturing a catalytic material in an economical and expeditious manner.

Another object. of lmy invention is to provide a method of hydrolytically preparing a catalytic material.

Other and further objects of my invention will appear from the following description.

In the accompanying drawings which form part of the instant specification and are to be read in conjunction therewith and in which like reierence'numerals are used to indicate like parts in the various views.

Figure 1 is a diagrammatic view of a portion of the apparatus capable of carrying out the method of my invention.

Figure 2 is a diagrammatic view of the Yremaining portion of apparatus capable'of carrying out the method of my invention.

water from tank 5 and pumped by pump 6 through pipe 'i into the digester 3. Ten percent 4 excess dilute sulphuric acid is used. The dilution is controlled by pump 8 which pumps water through pipe 9 into the pipe l0 into which sulphuric` acid passes from tank i through pipe il. The digester is vprovided with agitating means l2 'operated by any suitable means such as a motor i3. The following reaction will take place between the thorium oxide and the sulphuric acid:

When the solution is complete, 15` percent aqueous ammonia from tank lil is pumped through line l5 by pump i6 and agitation continued to cause precipitation of thorium hydroxide as follows:

The slurry is then withdrawn from the digester 3 through pipe Il, controlled by valve i6 and pumped by pump i9 through pipe 20 through a plate and frame filterv press 2l. Ii desired, slurry may be diluted with water to wash it as it is being introduced into the filter. For this purpose, water pumped by pump 8 may pass through line 9 past valve 24 through line 23 through pipe 22 into pipe 20.

The ammonium sulphate in solution is withdrawn from the filter through pipe 25. The thorium hydroxide is withdrawn from the iilter and conveyed by conveyor 26 operated by motor 2l into a digester 28. Nitric acid stored in tank 29 iiows through pipe 3U controlled by valve 3l and is diluted by water from pipe 32 controlled by valve 33v and passes through pipe 34 into the digester 28, about ten percent excess of dilute nitric acid being` used. `The thorium hydroxide and dilute nitric acid are agitated in digester 28 by agitating means 35 operated by motor 36 until solution is electedas follows:

Simultaneously with the solution of thorium oxide, metallic cobalt from hopper 31 is intro- Referrlng now to the drawings, thorium oxide from hopper l is fed past valve 2 into va digester 3. Sulphuric acid from tank 4 is diluted with openedand valve 42' being closed. The digester 39 is provided with agitating means 43 operated by a motor 44.

acogfcHNoseiHgo-l-acomos)2+2N0 It is impossible towrite the exact equation because other oxides of nitrogen may be given o. The oxides of nitrogen may be vented through pipe 44 controlled by valve 45. If desired, the oxides of nitrogen may be used to form nitric acid.

'I'he excess acid in both the cobalt nitrate and thorium nitrate solutions formed in digesters 39 and 28 respectively is neutralized with potassium carbonate. The cobalt nitrate solution is withdrawn from the digester 39 through pipe 48 controlled by valve 41 and introduced into a tank 48. 'I'he thorium nitrate solution formed in digester 28 is withdrawn through pipe 49 controlled by valve 59 and passed through pipe 5l into the tank 48. A solution of potassium carbonate is made in tank 52, potassium carbonate being introduced from a hopper 53 controlled by a valve 54 and Water being introduced through pipe 55 controlled by Valve 56. The tank 52 is provided with agitating means 51 operated by an electric motor 58. The potassium carbonate solution is withdrawn from the mixing tank 52 through pipe 59 controlled by valve 68 and introduced in desired amounts into the tank 48; Kieselguhr from hopper 6I is introduced into the tank 48 through valve 62, The tank 48 is provided with an agiating means 63 operated by an electric motor 64. It is to be understood that any other suitable support for the catalytic material may be employed such as nely divided clays, silica or the like, which would be introduced from hopper 6l instead oi the kieselguhr.

The potassium carbonate is introduced into a tankv 48 through line 59. During the precipitation, the agitation is very thorough in order to insure a uniform product. As will be clear from the process hereinafter described, potassium carbonate may be used for precipitation while consuming only the cheaperI sodium carbonate. Potassium carbonate gives better results than sodium carbonate and produces a more active catalyst. The reason `for this is unknown. While I do not wish to be bound by any theory, this may be because the sodium ions are adsorbed and subsequently decrease -catalyst activity. In the tank 48 the following reactions occur:

The slurry formed in tank 48 is withdrawn through pipe 65 controlled by valve 66 and pumped by pump 61 through a plate and frame -filter press 68. The filtrate containing a solution of potassium nitrate and potassium carbonate is withdrawn from the lter 88 through pipe 69 for passage to the nitric acid and potassium carbonate recovery operations shown in Figure 2. The illter cake comprising a mixture of basic cobalt carbonate (2C0CO3.3C0(OH)2) and thorium carbonate precipitated on the carrier, kieselguhr, is withdrawn from the lter and conveyed through duct 18 provided with a conveyor screw 1| operated by a motorV 12 to a washer 13, water being introduced into the Washer through pipe 14 into a mixing chamber 15. 'I'he Washer may be of any suitable type.

The slurry is Withdrawn from the washer through pipe 16 and pumped by pump llthrough pipe 18 to a settler 19 from which the washing water is withdrawn through pipe 80. The washed material is Withdrawn from the settler 19 and conveyed through duct by augur 8l, operated by motor 82, to a drier 83, which may be oi' any suitable construction. Air from any suitable source passes through pipe 84, through pipe controlled by valve 86 into a burner 81 which is provided with gaseous fuel through pipe 88. The fuel and air burn in chamber 89 and the products of combustion pass through duct 90, through the drier and are withdrawn therefrom through pipe 9|. trolled byyalve 93 to control the temperature. The temperature may be further controlled by recycling the exhaust gases from the drier through duct 94 controlled by damper 95. 'I'he dried material leaves the drier and passes to a vibrating screen 96, the nes being withdrawn through pipe 91 controlled by valve 98. The dried particles are withdrawn through spout 99. These particles are then put in the catalyst chambers where the carbonates are decomposed with hot air as follows:

'The cobalt oxide is then reduced with hydrogen at 800 F'. as follows:

The thorium oxide is not re'ducible at this temperature so that the resulting catalyst will be the kieselguhr containing metallic cobalt and thorium oxide which seems to promote the action of the cobalt catalyst.

As pointed out above, this catalyst is particularly adapted for the synthesis of hydrocarbons from mixtures of carbon monoxide and hydrogen though it is to be understood that it may be employedI for any suitable operation in which a nely divided metal deposited upon a carrier is desired. Instead of cobalt, I may use nickel, iron or any other suitable metal from which the nitrate may be formed by interaction with nitric acid and which, further, is suitable as a catalyst, employing the reactions analogous to those pointed out above as will be readily understood by those skilled in the art.

From the foregoing it will be clear that my process enables nitric acid to be used in preparing the initial solutions, while consuming only the cheaper sulphuric acid. It is only necessary that the acid will form a metallic salt which will react with a carbonate to form the metal carbonate for decomposition to the oxide, followed by its reduction to the metal. l

I prefer to use nitric acid in the confection of a cobalt catalyst because cobalt does not readily dissolve in sulphuric acid,'for example, and further, the presence of sulphur tends to poison the catalyst in a synthesis reaction.

Nitric acid is considerably more expensive than sulphuric acid and potassium carbonate is more expensive than sodium carbonate. 'Ihe nitric acid and the potassium carbonate, are used to form intermediate products and I propose to recover these for reuse.

The nitrate withdrawn from the filter 68 through pipe 69 `contains an excess of potassium carbonate in solution and potassium nitrate'. This flows through pipe 69 to tank |00. Magnesium -carbonate slurry, previously separated in the process, as will b e hereinafter pointed out, is introduced into tank |08 through pipe lill` Excess air may pass' through pipe 92 conv The magnesium carbonate, potassium carbonate and potassium nitrate is withdrawn from tank through ,pipe |02 and pumped by pump |03 through pipe |04 into a mixer |05 provided with agitati'ng means |06 driven by an electric motor |01. Carbon dioxide from tank |00 is pumped by pump |09 through pipe ||0 `and introduced into the mixing chamber which is maintained under moderate pressure by back pressure controlled valve The potassium is precipitated as a double salt according to the following reaction: y 3 (MgCO3.3H2O) |2KNO3+CO2=- Mg Non) 2-1-2 (KHCO3-MgCOs .41120) The double salt is insoluble.

'Ihe slurry formed in mixing chamber |05 is withdrawn therefrom through pipe ||2 and pumped by pump ||3 through filter press H0, the filtrate vcontaining magnesium nitrate in solution which is withdrawn through pipe ||5 and passed to mixer chamber H5. The lter cake containing potassium acid carbonateand magnesium carbonate is passed by conveyor screw ||1 through duct' ||0 inlto tank ||5 into which water through pipe is introduced. T-he solution is heated by steam introduced through pipe |21 to breakup the double salt and put potassium carbonate into solution. The slurry is withdrawn from .the tank H0 through pipe |22 and pumped by pump |23 through lter press |20, filtrate containing potassium carbonate in solution being withdrawn through pipe |25 for pumping by pump |20 through pipe |21 for passage to the tank |00 through pipe 69. The filter cake containing the magnesium carbonate is withdrawn from the filter |20 through duct |28 and conveyed through duct |29 by conveyor screw |30 to the mixer |3I. To the magnesium nitrate solution entering tank H5 is added a. solution of sodium carbonate withdrawn from tank |32 through pipe |33 controlled by valve |34. The magnesium nitrate and the sodium carbonate solution are agitated by a mixer |35 operated by a motor |36. The following reaction takes place:

The slurry is withdrawnv from .tank ||6 through pipe |31 and is pumped by pump |38 through pipe |39 to the lter press |40, the filtrate containing sodium nitrate being withdrawn through pipe IM for passage to the Vevaporator |42 in which the Walter is evaporated by heat supplied through a coil |43 by means of steam introduced through pipe |44. Dried sodium nitrate is conveyed through duct |45 by means of conveyor screw |46 operated by a motor |41 into a retort |40 into which is introduced 95 percent sulphuric acid from tank |49, .through pipe |50 controlled by valve |5| The sodium nitrate and the sulphuric acid react to form nitric acid as follows:

This reaction is weil known and has a broad commercial background. The nitric acid is distilled from the retort |08 by means of heat supplied to a coil |52 by suitable heating medium or by external heating. Nitric acid vapors pass overhead through pipe |50 and are condensed in condenser |55 to which a cooling medium is supplied through pipe |56. 'I'he condensate is Withdrawn from the condenser |55 through pipe |51 and collected in an accumulator tank |50 from which it is withdrawn through pfipe |50 and pumped by pump to pipe ISI, :to the nitric acid storage tank 20 shown in Figure 1. The sodium acid sulphate sludge is withdrawn from retort |48 through pipe |64 and is discarded.

The filter cake from filter press |40 comprising magnesium carbonate and magnesium hydroxide is withdrawn, through duct |62 and conveyed through duct |03 for passage through duct |20 with the magnesium carbonate filter cake from filter |24 into the mixing chamber |3I.

The lter cakes are put in the solution with carbon dioxide and water with the aid of vigorous mechanical agitation. Water is introduced into the mixing chamber |0| through pipe |55 and carbon dioxide is passed into the chamber |31 through pipe |06 controlled by valve |51. The following reaction will take place:

SMgcOazMgmH)asino-estema:

4Mg(HCO3) 2+5H2O The solution is withdrawn from the chamber |0| through pipe |50 controlled by valve |69 and passed into boiler |10 which is heated by steam coil |1| to which steam is introduced through pipe |12. The solution is boiled in boiler |10 with '.the resulting precipitation of magnesium carbonate in accordance with the following reaction:

4Mg (HCOa) 2+8H2O=4MgCOa3H2O+4CO2 The slurry containing the water and the magnesium carbonate in suspension is withdrawn from the pump |10 through pipe |10 and pumped by pump |14 through pipe |15 into a settler |16 from which water is decanted olf .through pipe |11. The thickened slurry containing magnesium carbonate is withdrawn from the settler through pipe |18 and pumped by pump |10 through pipe |0| into the tank |00 as the magnesium carbonate previously separated in the process.

By my method I am enabled to recover 95 percent of the potassium carbonate, about 90 percent of the magnesium carbonate and about per-,- cent of nitric acid, based on the nitrate radical present in the potassium nitrate.

It will be seen that I have accomplished the objects of my invention. I have provided an expeditious method of preparing catalysts comprising nely divided metals supported upon a siliceous material such is kieselguhr, silica or the like by hydrolytically depositing the metal carbonate upon the support, which carbonate can be easily decomposed to the metaloxide which is subsequently reduced to the metal.

By means of my process, the only nitric acid required is to make up the loss in the form of oxides of nitrogen and the only potassium car bonate is that required to make up for losses.

My vappliance may be used for re-working an old catalyst by dissolving the catalyst in nitric acid to form the metal nitrate followed by processing the same as in the case of a new catalyst.

It will be understood that certain features and sub-combinations are of utility and may be employed without reference to other features and sub-combinations. This is contemplated by and is within the scope of my claims. lit is further obvious that various changes may be made in details within the scope of my claims Without departing from the spirit of my invention. It is, therefore, to be understood that my invention is not to be limited to the specific details shown and described.

Having thus described my invention, I claim: l. A method of forming a catalyst comprising a finely divided metal deposited upon a support including the steps of forming a solution oi' the desired catalyst metal in nitric acid comprising a portion previously recovered in the process, suspending a finely divided inert siliceous catalyst support in said solution, precipitating the carbonate of the metal upon the Asupport and forming a corresponding amount of potassium nitrate by the addition of potassium carbonate to the solution, separating the support together with the precipitated metal carbonate from the solution of potassium nitrate, drying and heating said separated support and carbonate to decompose the carbonate to form the oxide of the metal in place upon the support, reducing the oxide to form the metal in linely divided form disseminated upon the support, adding magnesium carbonate to the filtrate containing potassium nitrate to form magnesium nitrate, 'reacting sodium carbonate with the magnesium nitrate to form sodium nitrate, reacting the sodium nitrate with sulfuric acid to form nitric acid, and returning the nitric acid to the process.

2. A method of forming a catalyst comprising a finely divided metal deposited upon a support including the steps of forming a solution of the desired catalyst metal in nitric acid comprising a portion previously recovered in the process, suspending a nely divided inert siliceous catalyst support in said solution, precipitating the carbonate of the metal upon the support and forming a corresponding amount of potassium nitrate by the addition of potassium carbonate to the solution, separating the support together with the precipitated metal carbonate from the solution of potassium nitrate, drying and heating said separated support and carbonate to decompose the carbonate to form the oxide of themetal in place upon the'support, reducing the oxide to form the metal in nely divided form disseminated upon the support, adding magnesium carbonate and carbon dioxide to the solution containing potassium nitrate to form soluble magnesium nitrate and an insoluble magnesium potassium magnesium carbonate, separating the potassium magnesium carbonate from the solution of magnesium nitrate, reacting sodium carbonate with the magnesium nitrate to form sodium nitrate, reacting the sodium nitrate with sulfuric acid to form nitric acid, returning the nitric acid to the process for reuse in forming a solution oi the catalyst metal, mixing water with the potassium magnesium carbonate and heating the mixture to decompose said carbonate to form soluble potassium carbonate and insoluble magnesium carbonate, and separating and returning the thus formed potassium carbonate for reuse in said precipitating step.

3. A method of forming a catalyst adapted for l use in the synthesis of hydrocarbons from mixtures of carbon monoxide and hydrogen, said catalyst comprising cobalt supported upon kieselguhr bearing a thorium oxide promoter which includes the steps of forming a solution of cobalt nitrate by the interaction of nitric acid and cobalt, simultaneously forming thorium hydroxide by the interaction of thorium sulphate and ammonia, reacting thorium hydroxide and nitric acid to form thorium nitrate, agitating the solution of cobalt nitrate and thorium nitrate with kieselguhr, precipitating cobalt carbonate and thorium carbonate from the agitated mixture upon the kieselguhr forming a corresponding amount of potassium nitrate by addition of potassium carbonate, separating the kieselguhr, and cobalt carbonate and thorium carbonate precipitated thereon from the potassium nitrate solution, passing the potassium nitrate solution to a recovered nitric acid recovery operation, returning the nitric acid to the process, drying the kieselguhr-cobalt carbonate-thorium carbonate precipitate, heating the precipitate to decompose the thorium and cobalt canbonates to cdbalt oxide and thorium oxide respectively, subjecting the mixture of metal oxides upon the kieseiguhr to a reduction step to reduce the cobalt oxide to metallic cobalt, the thorium oxide being irreducible under the conditions of the reducing step whereby the desired catalyst is formed.

4. A method as in claim4 3 wherein said nitric acid recovery operation comprises agitating the potassium nitrate filtrate and magnesium car,- bonate in the presence of carbon dioxide to form magnesium nitrate and insoluble potassium magnesium carbonate, separating the potassium magnesium carbonate from the magnesium nitrate solution, reacting the magnesium' nitrate in solution filtrate with sodium carbonate to form sodium nitrate and magnesium carbonate, separating the solution of sodium nitrate from the magnesium carbonate, evaporating the sodium nitrate solution to dryness, and reacting the sodium nitrate with sulphuric acid to form nitric acid.

GEORGE ROBERTS, JR.

cnanFIcATE'oF CORRECTION. l. Patent No. 2,gk14.,575. June 5, 1914.1.

GEORGE ROBERTS, JR.

ItV- is hereby certified that error appears, in the printed specification, of the above nmnberetl patent requiring correction as follows: Page 5, first column, line 2.5, for carbonateand 4read carbonate page 14, sec, ond column, line 25, claim 5, strike out the colma after "kiese1guhr";' line 27, seme clain, strike out "recovered" and insert the same'l before "nitric" in line 28, seme claim 5 'and -that: the said Lettere Patent should be` read withS-thie correction therein that the same may' conform to the record of 'the case in the Patent office.

signed and 'sealed this 1 ztn any or August, A. n. 19m.

Henry Ven Arsdale, (Seal) Acting Comi'seionergof Patents. 

